| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup or the like for effectively compensating for the influence of birefringence simply by electrical control without requiring any mechanical control. SOLUTION: The optical pickup PU projects a light beam B to an optical disk DK via a substrate PL, and at the same time, has a liquid crystal panel 3 for compensating birefringence that is generated when the light beam B is transmitted through the substrate P1 based on reflection light Br from the optical disk DK. In the optical pickup PU, the liquid crystal panel 3 is provided with an amplitude detection circuit 8 for compensating for birefringence by giving a cancellation phase difference, for canceling the birefringence to the light beam B transmitted through a liquid crystal layer by controlling the orientation direction of a liquid crystal molecule in the liquid crystal layer, and at the same time for generating a detection signal Sv for indicating the birefringence; and a driver 7 for controlling the liquid crystal panel 3 so that an orientation direction in a surface including a light axis is changed, while making constant the orientation direction of the liquid crystal molecule in a surface that is vertical to the light axis of the light beam B based on the detection signal Sv, and for generating a cancellation phase difference in the light beam B. |
